Trust comes from honesty and authenticity
In my opinion, trust is built through honesty and authenticity. In my experience, the quickest way to communicate both is to be willing to admit to weaknesses.
Be careful about which weaknesses you choose to share. But done well, it is very effective, and it is honest.
What that sounds like with a prospect
A lot of my work is helping consultants and fractionals build their pipeline on LinkedIn, in a non-salesy way.
When I talk with a prospective client, I tell them the truth: “This was not easy for me. It was difficult and humbling to fail at this before I figured out what worked.”
Why it works
Being willing to admit that makes people more open to believing the other things you say.
Psychologists have studied a version of this for a long time. In a 1966 experiment published in Psychonomic Science, Elliot Aronson, Ben Willerman, and Joanne Floyd had 48 college students listen to a recorded interview with a quiz contestant. When a highly capable contestant clumsily spilled coffee on himself, students rated him more attractive than the same capable contestant without the spill. When an average contestant spilled the coffee, his rating dropped. It became known as the pratfall effect, and the condition matters: a flaw helps most when people already see you as competent.
Faking it does not work. A 2018 paper in the Journal of Personality and Social Psychology by Ovul Sezer, Francesca Gino, and Michael Norton looked at humblebragging, which is bragging dressed up as a complaint or as humility. Across nine studies, humblebraggers were liked less and seen as less competent than people who simply bragged, and the reason was that they came across as insincere. Admitting a weakness that is real is the opposite of that.
I am not trying to manipulate anyone. It is the truth. It is not the only way to build trust, but it is the way that works well for me. For more on honesty with clients, read hard truths are how consultants earn trust, or book a networking chat.